← CVE catalog

CVE-2021-21311

High CVSS 7.2 Known exploited

Published 2021-02-11 · last changed 2026-06-17 · added to CISA KEV 2025-09-29

This one is being exploited in the wild.

CISA added CVE-2021-21311 to the Known Exploited Vulnerabilities catalog on 2025-09-29. Federal agencies are required to remediate it on a deadline. If you have affected machines, this is the class of finding that moves ahead of the rest of the queue.

The fix

We hold no Microsoft remediation data for CVE-2021-21311, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

Adminer is an open-source database management in a single PHP file. In adminer from version 4.0.0 and before 4.7.9 there is a server-side request forgery vulnerability. Users of Adminer versions bundling all drivers (e.g. `adminer.php`) are affected. This is fixed in version 4.7.9.

Sources

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N